In 1971 Apollo 15 astronaut David Scott performed a simple experiment. It was interesting because Astronaut Scott was standing on the surface of the Moon when he did it!

Your book shows (on page 50) a drawing of a feather and a coin falling through a vacuum inside a vacuum tube. (A vacuum is created by removing all the air from a container.) The photo on the same page shows a feather and an apple dropping through a vacuum. It's impossible to create a total vacuum on Earth, though. Astronaut Scott was on the Moon, which has no atmosphere. He was standing in the vacuum of space, which is nearly total. (Note that the Moon does have gravity. Gravity on the Moon is much less than gravity on the Earth. But things are pulled towards the surface of the Moon, just as they are on Earth.)

The movie below shows Astronaut Scott holding a hammer in his right hand, and a falcon feather in his left hand. He drops them at the same time. What happens? How is this different from what might happen in our lab?

"In my left hand I have a feather, and in my right, a hammer"

"One of the reasons we're here today is because of Galileo. He made an important discovery a long time ago"
"..about falling objects in a gravity field."

"What would be a better place to confirm his findings than on the Moon?"